The invention relates to a method of minimizing play in a valve operating mechanism of an internal combustion engine.
European Patent 267 687 discloses a valve operating mechanism for an internal combustion engine, wherein an inlet valve is actuated, depending on the instantaneous speed of the internal combustion engine, via a low-speed cam or a high-speed cam. To this end, two adjacently arranged valve-actuating levers are mounted on a common shaft and are kinematically coupled to one another via a coupling pin when the actuation of the inlet valve is to be effected via the high-speed cam. In the case of kinematic coupling of the two valve-actuating levers, the coupling pin projects into both a coupling bore arranged in the one valve-actuating lever and a coupling bore arranged in the other valve-actuating lever. Due to manufacturing tolerances for the cam shaft, the valve-actuating levers, their bearing spindles, the coupling pin and the coupling bores accommodating the latter, a relatively large play can develop at the coupling-pin location between the two valve-actuating levers. Such play has an adverse effect on the character of the valve-lift curve as well as on the inlet and exhaust valve overlap and thus on the volumetric efficiency of the internal combustion engine as well as on its idling residual-gas behavior. The consequence thereof is poor idling and poor performance.
It is the object of the present invention to provide a method by which these disadvantages can be reduced to a minimum.